diff --git a/lib/dns.js b/lib/dns.js
index 62faf32b690735..cbde0af2c0ac3d 100644
--- a/lib/dns.js
+++ b/lib/dns.js
@@ -309,11 +309,16 @@ function setServers(servers) {
       }
     }
 
-    const [, s, p] = serv.match(addrSplitRE);
-    ipVersion = isIP(s);
+    // addr::port
+    const addrSplitMatch = serv.match(addrSplitRE);
+    if (addrSplitMatch) {
+      const hostIP = addrSplitMatch[1];
+      const port = addrSplitMatch[2] || IANA_DNS_PORT;
 
-    if (ipVersion !== 0) {
-      return newSet.push([ipVersion, s, parseInt(p)]);
+      ipVersion = isIP(hostIP);
+      if (ipVersion !== 0) {
+        return newSet.push([ipVersion, hostIP, parseInt(port)]);
+      }
     }
 
     throw new ERR_INVALID_IP_ADDRESS(serv);
diff --git a/test/parallel/test-dns.js b/test/parallel/test-dns.js
index fb648544b95469..27f6f4a126d096 100644
--- a/test/parallel/test-dns.js
+++ b/test/parallel/test-dns.js
@@ -62,6 +62,19 @@ assert(existing.length > 0);
   ]);
 }
 
+{
+  // Various invalidities, all of which should throw a clean error.
+  const invalidServers = [
+    ' ',
+    '\n',
+    '\0',
+    '1'.repeat(3 * 4)
+  ];
+  invalidServers.forEach((serv) => {
+    assert.throws(() => dns.setServers([serv]), /TypeError.*ERR_INVALID_IP_ADDRESS/, `Unexpected error thrown for ${serv}`);
+  });
+}
+
 const goog = [
   '8.8.8.8',
   '8.8.4.4',